Mechanical properties of INCONEL 625 (marketing department of Shanghai HY Industry Co., Ltd)
We study this high-performance nickel alloy and explore its impressive mechanical properties that make it a widely used material.
An impressive nickel alloy, INCONEL 625 alloy is a wonder in the INCONEL alloy product line. Its many positive properties mean it has many different industrial uses, making it an especially versatile alloy.
This high-performance material is often praised for its excellent corrosion resistance, even in the harshest environments and highest temperatures. But that’s not its only feature; the alloy has been crafted to provide a wealth of physical and mechanical properties that help solve common engineering design problems.
Over the years, INCONEL 625 alloy has been developed to further enhance these properties. Since its first introduction in the 1960s, as a material for steam pipes, it has been improved to increase its creep resistance and weldability, thereby increasing its range of industrial applications.
1，Define Mechanical Properties
There are many factors to consider when selecting materials. It is important to evaluate the physical and mechanical properties of an alloy to see how these properties match the intended end use.
Physical properties refer to measurable properties, such as the electrical conductivity or melting point of an alloy. The fact that these properties are alloy compositions are useful points to consider.
However, the mechanical properties of the alloy are more useful for design engineers to compare the properties of different metal alloys to meet their requirements. Mechanical properties are the performance indicators of a material under different forces. This includes strength (tensile, fracture, fatigue, etc.), ductility and wear resistance.
Mechanical properties can be affected by how the alloy is processed, which is why some nickel alloys are hot or cold worked to obtain the proper balance of mechanical properties. When selecting a material, a balance is required—some materials perform well under certain conditions and in certain properties, but are weaker in others. Therefore, it is very important to choose the appropriate alloy strength and application range.
2，Main mechanical properties of INCONEL625 Inconel
While numerous tests are performed on nickel alloys to determine their mechanical properties, one of the most important is the tensile strength test. This characteristic is related to the amount of load the metal can withstand before breaking. Metals go through many important strength points before finally breaking. The material will first begin to deform and stretch until it reaches a point where that deformation is preserved (as opposed to reverting to the original shape). This is the yield strength. When the material reaches the load at which it will eventually break, this is the tensile strength. The more a material resists permanent deformation in shape, it is called the hardness of the alloy.
INCONEL625 has high strength and hardness. By cold working the alloy, the tensile strength of the material can be increased in moderate temperature service conditions. Some hardening occurs inside the alloy when exposed to intermediate temperatures.
Another key test performed on an alloy is to determine its strength, i.e. to observe its fatigue strength. This is how much repetitive stress a metal can withstand, although this is highly dependent on the level of stress the metal is subjected to, how often and for how long the stress is applied. The fatigue limit is usually expressed in terms of “cycles” that the metal can withstand. INCONEL 625 exhibits good room temperature fatigue strength, as well as solid state properties at elevated temperatures – which vary depending on whether the metal has been solution treated or annealed.
As an example of its exceptional fatigue strength, the endurance limit of INCONEL 625 alloy at room temperature using cold rolled annealed sheet under full reverse bending for 108 cycles was found to be 90,000 psi for smooth bar. The toughness of a material is usually measured by impact testing to see how well an alloy can absorb impact without breaking. This is usually done in different temperature ranges. Ductility is also tested to see how much a material can stretch without breaking and retain its new shape after the force is removed. Both toughness and ductility are affected at very low temperatures when the material is more prone to cracking. However, INCONEL 625 alloy retains its excellent toughness and ductility at temperatures as low as -320°F.
3，Machining INCONEL625
For optimum mechanical properties, INCONEL 625 alloy is usually hot worked, cold worked, or annealed below 1200°F. For hotter temperatures, it has the best performance when annealed or solution treated. Typically, if a part with optimum creep or fracture resistance is required, the material is usually solution treated.
It does need to be hand machined by experts to maintain these impressive mechanical properties. Since this material was developed to maintain great strength at high temperatures, care must be taken when hot working. It is easy to manufacture by thermoforming, but it requires very powerful equipment to do it. However, the material can be cold formed by standard processes, which has a beneficial effect on the mechanical properties of the alloy, such as increased tensile strength as described above.
